1. Field of the Invention
The present invention relates to a molding resin composition.
2. Description of the Prior Art
Moisture infiltrates the electrical wiring used in automobiles and the like, such as wiring harnesses, from areas such as grounded portions thereof. Generally, to keep such moisture from entering the automobile, it has been necessary, as in the wiring harness 50 shown in FIG. 5, to cut somewhere along its length a conductor 53 that is joined through a crimped portion 51 to a junction 52, and thus provide, for example, a portion 54 that is open to the atmosphere. As a result, the placement of the wiring imposes limitations on the design and other aspects, which is detrimental partially in terms of cost.
Also, there are methods for rendering electrical connectors waterproof or watertight by casting and curing, for example, a one-component silicone resin composition. Specifically, a process adapted for a connector 60 as shown in FIG. 6 is known that involves using a rubber member made of an ethylene-propylene copolymer (EPDM) or the like as a molding portion 61 and pouring such a material as one-component silicone resin composition into the region where a junction 62 and conductors 63 meet. However, because materials such as one-component silicone resin compositions have a long curing time, the resulting assembly must then be allowed to stand within the production facility for about 1 to 2 hours.
Various polyester resins are known which are good in such characteristics as flexibility, heat resistance, chemical resistance, oil resistance, extensibility and moldability. However, in hitherto known polyester resins which are good in some of the characteristics as above, the balance between the moldability and flexibility has been poor, making the use of such resins as hot-melt molding materials impossible. For instance, resins which have a low viscosity and are easy to mold have a very low flexibility once molded. On the other hand, resins endowed with a higher flexibility have been difficult to mold.
Additional examples include urethane hot-melt resins, polyamide hot-melt resins, EVA hot-melt resins, and silicone fillers. Unfortunately, these are difficult to use as hot-melt materials for molding.
To address the above problems, the inventor, along with colleagues, has earlier disclosed molding resin compositions which contain an aromatic polyester and can be used as hot-melt resin compositions for molding (see JP 2003-213099 A (Patent Document 1) and JP 2004-210893 A (Patent Document 2)).
Although nonrigid polyvinyl chloride (PVC) has hitherto been used as a wire coating material in harnesses and connectors, a changeover to polyolefin materials is underway in order to reduce the use of halogens.